 Vertical Oscillation arc welding, VOAW, is a commonly used technique for narrow gap gas metal arc welding, NGGMAW. It has been found to have some shortcomings, including incomplete fusion defects on the sidewalls and interlayers. To address these issues, a mathematical model was developed using the central composite design, CCD, and analysis of variance, and OVA, to determine the optimal welding parameters in different positions. Experiments were conducted in flat, vertical, and overhead positions to optimize the parameters. The results showed that the weld beads were free of defects in the sidewalls and interlayers when the optimized parameters were applied. This article was authored by Han Qinglu, Ruile Shui, Jianpeng Zhou, and others.